This invention relates to a catheter device for use in a blood vessel, particularly such a device employing a light source by which to illuminate the blood vessel.
There are presently a multitude of means by which catheter devices have been provided a light source for illumination of a blood vessel. Such means typically employ one or more optical fibers, for transmitting light of a selected frequency, the optical fibers terminating within the catheter at a predetermined position, the area around which it is desired to illuminate.
Because optical fibers are designed to guide light from one end of the fiber to the other, by causing the light to internally reflect, the light typically exits the fibers in substantially the direction along which the fiber is aligned. In a catheter device, this direction is typically also aligned with the blood vessel, owing to the need to maintain compact lateral dimensions. Thence, light leaving the fiber is generally not available for lateral illumination of the vessel walls unless the end of the fiber is treated in some manner to alter the course of light traveling therethrough from a generally forward direction to a lateral direction.
There are a number of references that treat or adapt the tip of an optical fiber in various ways to project light laterally onto a surface to be viewed. Examples are Ishibashi et al., U.S. Pat. No. 4,272,156 ("Ishibashi"), employing angled exit end faces of a fiber; Heller, U.S. Pat. No. 4,567,882 ("Heller"), employing a prism or bifurcated emitter portion of a fiber; Ector, U.S. Pat. No. 4,658,816 ("Ector"), employing a hemispherical tip formed on the end of a fiber; Mackin, U.S. Pat. No. 4,961,738 ("Mackin"), employing diverging optical fibers; Sugiyama et al., U.S. Pat. No. 5,036,834 ("Sugiyama"), employing a lens in close proximity to the end of a fiber; and Kozawa et al., U.S. Pat. No. 5,335,648 ("Kozawa"), employing a mirror member arranged at the outgoing end of a fiber.
All of the aforementioned approaches have drawbacks, however. Ishibashi requires a multitude of fibers having faces angled in different directions to project light laterally over a wide area. Requiring a large number of specially treated fibers is costly and demanding of valuable space, especially in a catheter device. Heller and Sugiyama require the cost and assembly complexity associated with an additional, precision part. Ector requires the manufacturing complexity and cost of forming a hemispherical end on a fiber. Mackin requires the manufacturing complexity and cost of creating a diverging optical fiber, as well as demands the space within the catheter to permit the divergence. Kozawa, as well, requires the cost of an additional part, complex assembly, and valuable space. All of the foregoing approaches require a relatively precise manufacturing process to achieve their aims.
Therefore, there is a need for a novel lighted catheter device and method for use and manufacture thereof that does not require precise manufacturing or complex assembly, and which requires minimal space.